1. Field of the Invention
The present invention is included in a technical field of semiconductor device fabrication and the like, and more specifically, relates to a substrate processing method and a substrate processing apparatus for performing, for example, processing by ultraviolet rays for a front face of an insulating film material applied on a substrate.
2. Description of the Related Art
In processes of semiconductor device fabrication, a layer insulating film is formed, for example, by an SOD (Spin on Dielectric) system. In this SOD processing system, a layer insulating film is formed by coating a wafer with a coating film while spinning the wafer and performing chemical processing, heat processing, or the like for the wafer by means of a sol-gel process, a silk method, a speed film method, a fox method, or the like.
When a layer insulating film is formed by the sol-gel process, for example, first an insulating film material, for example, a solution in which colloids of TEOS (tetraethoxysilane) are dispersed in an organic solvent is supplied onto a semiconductor wafer (hereinafter referred to as xe2x80x9cwaferxe2x80x9d). Thereafter, the wafer to which the solution is supplied is subjected to gelling processing, and then solvents are exchanged. Subsequently, the wafer on which solvents are exchanged undergoes heat processing.
In order to form the layer insulating film, for example, thick and flat on the wafer, application of about two to three coats of an insulating film material on the wafer is conventionally performed. However, the front face of the insulating film material after the application is generally large in contact angle, and thus there is a problem that when an insulating film material is further applied on the front face of the insulating film material, a front face of an upper layer insulating film material becomes uneven.
The present invention is made under the aforesaid circumstances and an abject thereof is to provide a substrate processing method and a substrate processing apparatus capable of forming an insulating film thick and flatter on a substrate.
Another object of the present invention is to provide a substrate processing method and a substrate processing apparatus capable of efficiently making a front face of an insulating film material smaller in contact angle.
To solve the aforesaid problem, according to a first aspect of the present invention, a substrate processing method, comprising the steps of: applying an insulating film material on a substrate; performing processing by ultraviolet rays for a front face of the applied insulating film material; and further applying an insulating film material on the applied insulating film material after the ultraviolet-ray processing step, is provided.
According to the above configuration, processing by ultraviolet rays, for example, processing including ultraviolet-ray irradiation is performed for the front face of the insulating film material, whereby the contact angle of the front face becomes smaller. Therefore, when an insulating film material is applied on the aforesaid front face by, for example, spin coating, the material smoothly spreads, and projections and depressions never occur on a front face of an upper layer insulating film material. Consequently, it is possible to form the insulating film thick and flatter on the substrate.
According to a second aspect of the present invention, a substrate processing method, comprising the steps of: applying an insulating film material on a substrate; applying ultraviolet rays to a front face of the insulating film material in an inert gas atmosphere; and thereafter bringing an atmosphere over the insulating film material to an oxygen atmosphere, is provided.
According to the above configuration, processing by ultraviolet rays, for example, processing including ultraviolet-ray irradiation is performed for the front face of the insulating film material, whereby the contact angle of the front face becomes small. Therefore, when a material of some kind is applied on the aforesaid front face by, for example, spin coating, the material smoothly spreads, and projections and depressions never occur on a front face of the material.
According to a third aspect of the present invention, a substrate processing apparatus, comprising: a holding plate for holding a substrate; an ultraviolet-ray irradiation lamp disposed above the holding plate for applying ultraviolet rays to a front face of the substrate; means for bringing a portion between the substrate held on the holding plate and the ultraviolet-ray irradiation lamp to an inert gas atmosphere; and means for switching at least the inert gas atmosphere over the front face of the substrate held on the holding plate to an oxygen atmosphere, is provided.
In the above configuration, the portion between the substrate held on the holding plate and the ultraviolet-ray irradiation lamp is brought into the inert gas atmosphere, ultraviolet rays are applied onto the substrate from the ultraviolet-ray irradiation lamp, and thereafter the inert gas atmosphere over the front face of the substrate is switched to the oxygen atmosphere, so that a front face of an insulating film can be efficiently made smaller in contact angle.
According to a fourth aspect of the present invention, a substrate processing apparatus, comprising: a holding plate for holding a substrate and ascendable and descendable between a first area and a second area below the first area; a vertically driving mechanism for vertically driving the holding plate between the first area and the second area; an ultraviolet-ray irradiation lamp disposed above the holding plate for applying ultraviolet rays to a front face of the substrate held by the holding plate; means for blasting an inert gas toward the first area; and means for blasting oxygen gas toward the second area, is provided.
According to the above configuration, the inert gas atmosphere can be switched to the oxygen atmosphere only by lowering the substrate from the first area to the second area, and the oxygen atmosphere can be switched to the inert gas atmosphere only by raising the substrate from the second area to the first area. Consequently, a front face of an insulating film can be efficiently made smaller in contact angle by raising and lowering the substrate above the holding plate.
According to a fifth aspect of the present invention, a substrate processing apparatus, comprising: a holding plate for holding a substrate to be ascendable and descendable between a first area and a second area below the first area; a vertically driving mechanism for vertically driving the substrate held by the holding plate between the first area and the second area; an ultraviolet-ray irradiation lamp disposed above the holding plate for applying ultraviolet rays to a front face of the substrate held by the holding plate; means for blasting an inert gas toward the first area; and means for blasting oxygen gas toward the second area, is provided.
According to the above configuration, the inert gas atmosphere can be switched to the oxygen atmosphere only by lowering the holding plate holding the substrate from the first area to the second area, and the oxygen atmosphere can be switched to the inert gas atmosphere only by raising the holding plate from the second area to the first area. Consequently, a front face of an insulating film can be efficiently made smaller in contact angle by raising and lowering the holding plate.
According to a sixth aspect of the present invention, a substrate processing apparatus, comprising: a holding plate for holding a substrate and rotatable; a rotationally driving mechanism for rotationally driving the holding plate; an ultraviolet-ray irradiation lamp, disposed above the holding plate along at least a radial direction of rotation of the holding plate, for applying ultraviolet rays to the substrate held by the holding plate; an inert gas blast portion, disposed along one side of the ultraviolet-ray irradiation lamp, for blasting an inert gas toward the front face of the substrate held on the holding plate; and an oxygen gas blast portion, disposed along the other side of the ultraviolet-ray irradiation lamp, for blasting oxygen gas toward the front face of the substrate held on the holding plate, is provided.
According to the above configuration, when the holding plate is rotated, the inert gas is first blasted to the front face of the substrate held on the holding plate, whereby the front face of the substrate is brought into the inert gas atmosphere and then irradiated with ultraviolet rays. Thereafter, the oxygen gas is blasted to the front face of the substrate, whereby the front face of the substrate is brought into the oxygen atmosphere. The holding plate is continuously rotated, whereby the aforesaid operations are repeated. Consequently, a front face of an insulating film can be efficiently made smaller in contact angle.
These objects and still other objects and advantages of the present invention will become apparent upon reading the following specification when taken in conjunction with the accompanying drawings.